Semiconductor device and a method of manufacturing the same and designing the same

ABSTRACT

There is provided a technique for improving the flatness at the surface of members embedded in a plurality of recesses without resulting in increase of time required for manufacturing processes. According to this technique, the dummy patterns can be placed up to the area near the boundary BL between the element forming region DA and dummy region FA by placing the first dummy pattern DP 1  of relatively wider area and the second dummy pattern DP 2  of relatively small area in the dummy region FA. Thereby, the flatness of the surface of the silicon oxide film embedded within the isolation groove can be improved in the entire part of the dummy region FA. Moreover, increase of mask data can be controlled when the first dummy patterns DP 1  occupy the relatively wide region among the dummy region FA.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a semiconductor device and a method of manufacturing the same and particularly to the technique that can effectively adapted to a semiconductor device including a flattening process utilizing the CMP (Chemical Mechanical Polishing) method in the manufacturing process thereof.

[0002] Trench isolation is one of the isolation methods for electrically isolating adjacent semiconductor elements. In this trench isolation method, grooves are provided on a semiconductor substrate which becomes an element isolation region and these grooves are filled with insulation films.

[0003] This trench isolation is formed, for example, with the following method. First, the grooves are formed in the depth, for example, of about 0.4 μm to the element isolation region of the semiconductor substrate with the dry etching method and thereafter the first insulation film is formed in the thickness, for example, of about 20 nm at the surface where the semiconductor substrate is exposed by conducting the thermal oxidation process to the semiconductor substrate. Thereafter, the second insulation film is deposited on the semiconductor substrate to fill the inside of the grooves and then the trench isolation is formed by removing the second insulation films at the outside side of the grooves and leaving the second insulation film only at the inside of the grooves through polishing of the surface of this second insulation film, for example, with the CMP method.

[0004] When the width of the element isolation region becomes relatively large, the polishing rate of the second insulation film becomes high in the local area in the CMP process and thereby the so-called dishing phenomenon is easily generated to generate a “recess” at the central area of grooves. However, several methods have been proposed to improve the flatness at the surface of the second insulation film in the element isolation region by controlling such dishing phenomenon. A method for providing a dummy pattern is one of such several methods.

[0005] For example, the Japanese Patent Application Laid-Open No. Hei 10(1998)-92921 corresponding to the U.S. Pat. No. 5,885,856 discloses a method in which each dummy structure is placed in the non-active device area to make equal the occupation density in the non-active device area and active device area and thereby the polishing rate is equalized for the entire part of the semiconductor substrate surface.

[0006] Moreover, the inventors of the present invention discussed a method of placing the dummy patterns in the regular manner. The technique explained below has been discussed with the inventors of the present invention and its outline is as follows.

[0007]FIG. 28 shows the first dummy pattern placing method which the inventors of the present invention have discussed.

[0008] A plurality of dummy patterns DPA₁ are regularly placed in a dummy region (region at the outside of the frame of broken line in the figure) FA, where semiconductor elements are not formed, other than the element forming region (region within the frame of broken line in the figure), where the semiconductor elements are formed. A plurality of dummy patterns DPA₁ are formed in the equal shape and size and these dummy patterns are extensively placed with the same interval in the dummy region FA.

[0009] The element forming region DA and dummy region FA other than the active region AC are element isolation region IS and the trench isolation is usually formed in the entire part of this isolation region IS. Therefore, this method for regularly placing the dummy patterns is accompanied with a problem that the dishing phenomenon is easily generated during the CMP process, particularly in the dummy region FA isolated from the active region AC. However, it is now possible to prevent such dishing phenomenon in the dummy region FA by placing a plurality of dummy patterns DP₁ and thereby flatness at the surface of the embedding insulation film in the dummy region FA can be improved.

[0010]FIG. 29 shows the second dummy pattern placing method which the inventors of the present invention have discussed. Like the FIG. 28 explained above, a plurality of dummy patterns DPA₂ are regularly placed in the dummy region FA, where the semiconductor elements are not formed, other than the element forming region DA where the semiconductor elements are formed and thereby the dishing in the dummy region FA can be prevented. Size of the dummy patterns DPA₂ is smaller than the size of the dummy patterns DPA₁ and the dummy patterns DPA₂ can be placed up to the dummy region FA near the boundary BL (indicated with a frame line in the figure) between the element forming region DA and dummy region FA.

SUMMARY OF THE INVENTION

[0011] However, according to the investigation with the inventors of the present invention, there has been the rise of a problem that when the dummy structures are placed in the non-active device area, some dummy structures are complicated in the shape thereof and the insulation film is not perfectly embedded within the internal side of the dummy structures which are particularly defined. Moreover, it has also been considered that the time required for the manufacturing process is extended because the process for removing the dummy structures that are too small to be formed is required.

[0012] In addition, the inventors of the present invention have also found that there exists a following problem in the first dummy pattern placing method and the second dummy pattern placing method.

[0013] In the first dummy pattern placing method, since the size of the dummy patterns DAP₁ is relatively large, a region where the dummy patterns DPA₁ cannot be placed is generated in the dummy region FA near the boundary BL between the element forming region DA and dummy region FA and if this region is extended relatively, it is apparent that the dishing phenomenon is generated.

[0014] In the second dummy pattern placing method, since the size of the dummy patterns DPA₂is relatively smaller, the dummy patterns DPA₂ may be placed up to the area near the boundary BL between the element forming region DA and dummy region FA. Thereby, since the dummy patterns DPA₂ may be placed also in the region where the dummy patterns DPA₁ cannot be placed, the second dummy pattern placing method can further improve the flatness of the surface of the embedded insulation film up to the dummy region FA near the boundary BL in comparison with the first dummy pattern placing method.

[0015] However, when the second dummy pattern placing method is introduced, the number of dummy patterns DPA₂ placed in the dummy region FA increases and thereby the coordinate data required for generating a mask remarkably increases. As a result, there rises a problem that the arithmetic processing time in a computer increases and moreover the time required for drawing the patterns on the mask substrate also increases and thereby the throughput in formation of mask is remarkably deteriorated. Particularly, when the second dummy pattern placing method is employed for ASIC (Application Specific Integrated Circuit: integrated circuit for particular application), the time required to generate the mask is extended, resulting in a problem that a problem is still left for development of ASIC within a short period of time.

[0016] It is therefore an object of the present invention to provide a technique to improve the flatness of the surface of members embedded in a plurality of recesses.

[0017] It is another object of the present invention to provide a technique to improve the flatness of the surface of members embedded in a plurality of recesses without extension of the time required for the manufacturing process of a semiconductor device.

[0018] The objects explained above, other objects and novel features of the present invention will become more apparent from description of the present invention and the accompanying drawings thereof. The typical inventions of disclosed in the present invention will be briefly explained below.

[0019] (1) In the semiconductor device of the present invention, there are provided an element forming region where circuit elements are specified with the boundary and a dummy region where circuit elements adjacent to the boundary are not formed. The dummy region has at least two dummy pattern groups, each dummy pattern group allocates a plurality of dummy patterns in the same occupation shape on the plane and in the same size with isolation like a matrix keeping also the equal interval between the patterns, and the sizes of a plurality of dummy patterns in the row direction and/or column direction are different among the dummy pattern groups.

[0020] (2) A method of manufacturing a semiconductor device of the present invention relates to the method of manufacturing a semiconductor device in which an element forming region where circuit elements are formed and a dummy region where circuit elements are not formed are specified with a boundary and at least two dummy pattern groups are formed in the dummy region, comprising a process to form the first isolation groove for specifying an active region of the element forming region to the main surface of a semiconductor substrate and the second isolation groove for dividing, in the matrix shape, a plurality of dummy patterns forming each dummy pattern group in the dummy region, a process to deposit an insulation film covering the element forming region and dummy region to embed the first isolation groove and second isolation groove and a process to remove the insulation film at the outside of the first isolation groove and second isolation groove by polishing the surface of insulation film, thereby a plurality of dummy patterns in the same occupation shape on the plane and in the same size are formed in each dummy pattern group but the sizes of dummy patterns in the row direction and/or column direction are different among the dummy pattern groups.

[0021] (3) A method of designing a semiconductor device of the present invention relates to a method of designing a semiconductor device in which an element forming region where circuit elements are specified with the boundary and a dummy region where circuit elements adjacent to the boundary are provided, the dummy region has at least two dummy pattern groups, a plurality of dummy patterns in the same occupation shape on the plane and in the same size are placed in separation like a matrix shape in each dummy pattern group and the sizes of a plurality of dummy patterns in the low direction and/or column direction are different among the dummy pattern groups, wherein comprising a process to allocate, after specifying the element forming region and dummy region with the boundary, a plurality of dummy patterns for each dummy pattern group to generate a mesh of the size adding a size of one side of the dummy pattern forming the dummy pattern group and a size of space among the adjacent dummy patterns for each dummy pattern group and allocate the dummy patterns within the mesh in the region where placement of dummy patterns is prohibited.

[0022] According to the means explained above, a plurality of dummy patterns can be placed up to the area near the boundary between the element forming region and dummy region. Thereby, the flatness of the surface of insulation film embedded in the isolation grooves can be improved in the entire part of the dummy region.

[0023] Moreover, since a relatively wide region among the dummy region can be occupied with a plurality of dummy patterns of relatively wider area, while the remaining relatively narrow region can be occupied with a plurality of dummy pattern of relatively narrow area, increase in the number of placed dummy patterns can be controlled. Therefore, increase in amount of coordinate data on the occasion of generating a mask can also be controlled in view of controlling the increase of the arithmetic processing time of computer and time for drawing a pattern on the mask substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a plan view of the essential portion of an example of a logic integrated circuit device as the embodiment 1 of the present invention.

[0025]FIG. 2 is a cross-sectional view along the line A-A of FIG. 1.

[0026] FIGS. 3(a) and 3(b) are plan views for explaining a pitch and a size of dummy patterns.

[0027]FIG. 4 is a plan view for explaining an example of placement of the dummy patterns.

[0028]FIG. 5 is a process diagram showing an example of a pattern manufacturing method.

[0029]FIG. 6 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0030]FIG. 7 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0031]FIG. 8 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0032]FIG. 9 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0033]FIG. 10 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0034]FIG. 11 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0035]FIG. 12 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0036]FIG. 13 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0037]FIG. 14 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0038]FIG. 15 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0039]FIG. 16 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 1 of the present invention.

[0040]FIG. 17 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 2 of the present invention.

[0041]FIG. 18 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 2 of the present invention.

[0042]FIG. 19 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 3 of the present invention.

[0043]FIG. 20 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 3 of the present invention.

[0044]FIG. 21 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 3 of the present invention.

[0045]FIG. 22 is a cross-sectional view of the essential portion of a semiconductor substrate in the process sequence for an example of a method of manufacturing a logic integrated circuit device as an embodiment 3 of the present invention.

[0046]FIG. 23 is a plan view of the essential portion of an example of the other logic integrated circuit device as an embodiment 4 of the present invention.

[0047]FIG. 24 is a plan view for explaining a pitch and a size of dummy patterns.

[0048]FIG. 25 is a plan view of the essential portion of an example of dummy patterns of wiring as an embodiment 5 of the present invention.

[0049]FIG. 26 is a plan view for explaining a pitch and a size of dummy patterns of wiring.

[0050]FIG. 27 is a cross-sectional view of the essential portion as an example of a logic integrated circuit device using dummy patterns for the wiring as an embodiment 5 of the present invention.

[0051]FIG. 28 is a plan view showing the first dummy pattern placement method discussed by the inventors of the present invention.

[0052]FIG. 29 is a plan view showing the second dummy pattern placement method discussed by the inventors of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] The preferred embodiments of the present invention will be explained in detail with reference to the accompanying drawings. In the following explanation of the preferred embodiments, the like elements are designated with the like reference numerals throughout the accompanying drawings and the same explanation is never repeated.

[0054] In regard to the “shape” explained in the present embodiment, the shape expression such as “square shape” and “rectangular shape” includes the shape on the design concept, shape of mask pattern on the data, shape on the mask and shape of real pattern on the patterned integrated circuit device and also substantially includes the shape where corners are a little deformed from the geographical shape due to the problem in the process such as lithography.

[0055] (Embodiment 1)

[0056] A placement example of dummy patterns as the embodiment 1 of the present invention will be explained with reference to FIGS. 1 to 5. FIG. 1 is a plan view of the essential portion showing an example of a logic integrated circuit device. FIG. 2 is a cross-sectional view along the line A-A of FIG. 1. FIG. 3 is a plan view for explaining a pitch and a size of the dummy patterns. FIG. 4 is a plan view for explaining an example of placement of the dummy patterns. FIG. 5 is a process diagram showing an example of a method of generating the dummy patterns.

[0057] As shown in FIG. 1, the internal side of the boundary BL indicated with a broken line shows the element forming region DA where semiconductor elements are formed, while the external side of the boundary BL shows the dummy region FA where semiconductor elements are not formed.

[0058] The boundary BL between the element forming region DA and dummy region FA is determined from a layout of the conductive film existing on the element isolation region IS and a layout of the active region AC. Since a problem such as increase of capacitance load is generated when a dummy pattern is formed at the lower part of the conductive film, it is required to determine the boundary BL to provide non-overlapping of the conductive film and dummy pattern. In the embodiment 1 of the present invention, the boundary BL is determined considering the allowable size required for reduction of such capacitance load and aligning accuracy in the lithography on the basis of the layout of conductive film and layout of active region AC extending on the element isolation region IS.

[0059] As shown in FIGS. 1 and 2, the CMOSFETs (Complementary Metal Oxide Semiconductor Field Effect Transistors) C₁, C₂, C₃ are formed in the element forming region DA. The active region AC is specified with the element isolation region IS where the silicon oxide film 3 is embedded in the isolation grooves 2 a formed on the main surface of the semiconductor substrate 1.

[0060] On the main surface of semiconductor substrate 1, a p-type well 4 and an n-type well 5 are formed and an n-channel MISFET (Metal Insulator Semiconductor FET) is formed in the p-type well 4, while an n-channel MISFET in the n-type well 5. On the main surface of the semiconductor substrate 1, a gate electrode 7 is formed via a gate insulation film 6 of the n-channel MISFET and p-channel MISFET. The gate insulation film 6 may be formed of a silicon oxide film formed, for example, with the thermal oxidation method and the gate insulation film 7 may be formed of a polycrystalline silicon film formed, for example, with the CVD (Chemical Vapor Deposition) method. At the surface of the polycrystalline silicon film, a silicide layer for reduction of electric resistance may be formed. Moreover, the gate electrode 7 is formed extending on the element isolation region IS from the active region AC.

[0061] A side wall spacer 8 is formed at the side wall of the gate electrode 7 of the n-channel MISFET and p-channel MISFET. This side wall spacer 8 may be formed, for example, of a silicon oxide film or a silicon nitride. Moreover, the source and drain expanding regions 9 a are formed sandwiching a channel region in the p-type wells 4 in both sides of the gate electrode 7 of the n-channel MISFET and moreover the source and drain expanding regions 9 b are formed at the external side of the source and drain expanding regions 9 a. In the same manner, although not shown particularly, the source and drain expanding regions are formed sandwiching the channel region in the n-type wells 5 in both sides of the gate electrode 7 of the p-channel MISFET and moreover the source and drain diffusing regions are formed at the outside of the source and drain expanding regions. The source and drain of the n-channel MISFET and p-channel MISFET are formed in the so-called LDD (Lightly Doped Drain) structure.

[0062] The CMOSFETs C₁, C₂, C₃ formed in the element forming region DA are covered with an interlayer insulation film 10 which is provided with the p-type well and n-type well of the active region AC and a contact hole 11 reaching the gate electrode. The interlayer insulation film 10 is formed, for example, of a silicon oxide film and the surface thereof is preferably flattened with the etch back method or CMP method. On the interlayer insulation film 10, wirings are formed but these wirings are not shown.

[0063] In the dummy region FA, a plurality of the first dummy patterns DP₁ of relatively large area (indicated as the thin-meshed areas in FIG. 1) and a plurality of the second dummy patterns DP₂ of relatively narrow area (indicated as the thick-meshed areas in FIG. 1) are regularly placed. As shown in FIG. 3(a), the first dummy pattern DP₁ has a side in size of La in both row and column directions and is structured as a square semiconductor island corresponding to the active region AC, occupying the relatively wide region among the dummy region. On the other hand, the second dummy pattern DP₂ as a side in size of Lb in both row and column directions and is structured as a square semiconductor island corresponding to the active region AC and is placed in the relatively narrow region of the dummy region.

[0064] Here, a size La of one side of the first dummy pattern DP₁ is set larger than a size Lb of one side of the second dummy pattern DP₂, but a size of space between the adjacent first dummy patterns DP₁ and a size of space between the adjacent second dummy patterns DP₂ are set in the equal size of space Sa and the first dummy patterns DP₁ and the second dummy patterns DP₂ are respectively isolated in the identical space.

[0065] Moreover, as shown in FIG. 4, a pattern size which is equal to the size La of a side of the first dummy pattern DP₁+space size Sa is equal, in both row and column directions, to the integer times of a pattern size which is equal to the size Lb of a side of the second dummy pattern DP₂+space size Sa, satisfying the relationship of La+Sa=N×(Lb+Sa) (N is an integer 1 or larger, N≧1). Thereby, since the first dummy pattern DP₁ and second dummy pattern DP₂ which are in different sizes can be regularly placed in the plural number in the dummy region FA, increase of the arithmetic processing time of computer can be controlled even when the coordinate data for generating a mask increases.

[0066] Moreover, the sizes La of the first dummy pattern DP₁, Lb of the second dummy patterns DP₂ and space size Sa are set to the minimum allowable size (minimum size allowable for pattern design) or more. If these sizes become smaller than the minimum allowable size, various problems such as peeling of resist pattern, manufacturing failure of isolation grooves in the dry-etching process or embedding failure of silicon oxide film into the isolation grooves are generated at the time of forming the element isolation region IS. For example, the size La of a side of the first dummy pattern DP₁ is set to 2.0 μm, while the size Lb of a side of the second dummy pattern DP₂ is set to 0.8 μm and the space size Sa is set to 0.4 μm.

[0067] Next, the dummy pattern placement method will be explained with reference to FIG. 5. The placement data of dummy pattern is generated using an automatic program installed in a computer. Next, a dummy pattern is drawn on the mask substrate on the basis of this placement data and the dummy pattern is then transferred to a semiconductor substrate via the mask. Here, the method of generating the placement data of the first dummy pattern DP₁ and second dummy pattern DP₂ using the automatic program is explained.

[0068] First, the placement prohibiting region of the first and second dummy patterns DP₁ and DP₂ (element forming region DA) is obtained (process 100 of FIG. 5). As explained above, the placement prohibiting region is determined considering the allowable size required for reduction of capacitance load and aligning accuracy in the lithography technique based on the layout of the conductive film extending on the element isolation region IS and layout of the active region AC. Namely, the specified size data is respectively added to the coordinate data of conductive film extending on the element isolation region IS and the coordinate data of the active region AC and the coordinate data of the placement prohibiting region can be obtained by obtaining the OR of all data obtained. For example, the region isolated by 2 μm from the active region AC where the CMOSFETs C₁, C₂, C₃ are formed is designated as the first placement prohibiting region, the region isolated by 1 μm from the gate electrodes of the CMOSFETs C₁, C₂, C₃ as the second placement prohibiting region and the OR region between the first and second placement prohibiting regions as the placement prohibiting region of the first and second dummy patterns DP₁ and DP₂.

[0069] Next, the first dummy patterns DP, of relatively large area are placed in the greater part of the dummy region FA (process 101 of FIG. 5). For example, after a mesh is formed in the first pitch on the entire surface of the semiconductor substrate 1, the mesh of the placement prohibiting region of the first and second dummy patterns DP₁ and DP₂ is removed. Otherwise, after the mesh is formed in the first pitch on the entire surface of the semiconductor substrate 1, the mesh of the placement prohibiting region of the first and second dummy patterns DP₁ and DP₂ is removed and moreover the mesh of the minimum allowable size or less is removed. Thereafter, the first dummy pattern DP₁ is placed in the mesh. Here, the first pitch is a pattern size (La+Sa) which is equal to the size La of a side of the first dummy pattern DP₁+space size Sa.

[0070] Next, the placement prohibiting region of the second dummy pattern DP₂ of relatively smaller area is obtained (process 102 of FIG. 5). The placement prohibiting region of the second dummy pattern DP₂ is designated by adding the region where the first dummy patterns DP₁ are placed extensively in the process 101 to the placement prohibiting region of the second dummy pattern DP₂.

[0071] Next, the second dummy patterns DP₂ of relatively smaller area are placed in the dummy region FA (process 103 of FIG. 5). For example, after the mesh is generated in the second pitch on the entire surface of the semiconductor substrate 1, the mesh of the placement prohibiting region of the second dummy pattern DP₂ is removed. Or, after the mesh is generated in the second pitch to the entire surface of the semiconductor substrate 1, the mesh in the placement prohibiting region of the second dummy pattern DP₂ is removed and moreover the mesh of the minimum allowable size or less is removed. Thereafter, the second dummy pattern DP₂ is placed in the mesh. Here, the second pitch is a pattern size (Lb+Sa) which is equal to the size Lb of a side of the second dummy pattern DP₂+space size Sa and moreover the second pitch of the second dummy pattern DP₂ is equal to 1/integer (N) of the first pitch of the first dummy pattern DP₁, namely equal to ½. Also, from the point of view of easier placement of the second dummy pattern DP₂, it is preferable to set the second pitch of the second dummy pattern DP₂ to 1/(an integer of the first pitch of the first dummy pattern DP₁).

[0072] In this embodiment 1, a plurality of first dummy patterns DP₁ are placed in the dummy region FA isolated from the element forming region DA and the a plurality of dummy patterns DP₂ are placed in the dummy region FA near the element forming region DA, but the present invention is, of course, not limited to this embodiment 1. For example, a plurality of first dummy patterns DP₁ may be placed in the dummy region FA near the element forming region DA and a plurality of second dummy patterns DP₂ may be placed in the dummy region FA far from the element forming region DA. Otherwise, a plurality of dummy patterns DP₁ may be placed almost to the entire surface of the dummy region FA and a plurality of second dummy patterns DP₂ may also be placed among the adjacent first dummy patterns DP₁ where the second pitch is generated.

[0073] Moreover, in the embodiment 1, examples of the CMOSFETs C₁, C₂, C₃ are shown as the semiconductor elements formed in the element forming region DA, but these semiconductor elements may be substituted for the other semiconductor elements, for example, the Bi-CMOS transistor.

[0074] As explained above, according to the embodiment 1, since the first dummy patterns DP₁ and second dummy patterns DP₂ can be placed in the region up to the boundary BL between the element forming region DA and dummy region FA, the flatness of the surface of the silicon oxide film 3 embedded within the isolation grooves 2, 2 a can be improved in the entire region of the dummy region FA.

[0075] Moreover, the number of second dummy patterns DP₂ of the relative smaller area to be placed can be reduced by occupying the relatively wider region of the dummy region FA with the first dummy patterns DP₁ of relatively wider area and thereby increase of the data amount of mask can also be controlled. Moreover, the first dummy pattern DP₁ and second dummy pattern DP₂ can be expressed with the least data of the origin coordinate and XY coordinate by setting the shape of the first dummy pattern DP₁ and second dummy pattern DP₂. Accordingly, increase of coordinate amount for generating a mask can be controlled and thereby increase of arithmetic processing time of computer and time for drawing a pattern on the mask substrate can also be controlled.

[0076] Next, an example of the method of manufacturing a logic integrated circuit device of the embodiment 1 will be explained following the process sequence with reference to FIGS. 6 to 16.

[0077] First, as shown in FIG. 6, a semiconductor substrate 1, for example, consisting of a p-type single crystal silicon is prepared. Next, this semiconductor substrate 1 is thermally oxidized and a thin silicon oxide film 12 is formed on the surface thereof in the thickness as thin as about 10 nm. Thereafter, a silicon nitride film 13 is deposited in the thickness of about 120 to 200 nm with the CVD method on the upper layer and the silicon nitride film 13, silicon oxide film 12 and semiconductor substrate 1 are sequentially dry-etched using a resist pattern as the mask in order to form the isolation grooves 2, 2 a in the depth of about 0.3 to 0.4 μm on the semiconductor substrate 1. In the dummy region FA, the first dummy pattern DP₁ and second dummy pattern DP₂ are provided to avoid that the entire region becomes the isolation groove.

[0078] Next, in view of cleaning the interface condition of the internal wall of the isolation grooves 2, 2 a, the semiconductor substrate 1 is subjected to the thermal oxidation process to form, although not shown, a silicon oxide film as thin as about 10 to 30 nm on the exposed surface of the semiconductor substrate 1. Subsequently, as shown in FIG. 7, a silicon oxide film 3 is deposited with the CVD method or plasma CVD method on the semiconductor substrate 1. Film thickness of this silicon oxide film 3 is, for example, about 600 to 700 nm and this silicon oxide film 3 is formed in such a profile that the surface of the silicon oxide film 3 embedded to the relatively large isolation groove 2 a to be easily formed in the boundary BL or element forming region DA becomes higher than the surface of the silicon nitride film 13.

[0079] Next, a mask of an inverted mask of the isolation groove 2 is prepared. On this mask, only the pattern of the relative large isolation groove 2 a to be easily formed in the boundary BL or element forming region DA among the inverted pattern is depicted and the pattern smaller than the particular size, for example, of 0.6 μm is removed. Using this mask, a resist pattern 14 is formed on the silicon oxide film 3 and the silicon oxide film 3 is removed by the etching process in the amount of about ½ (for example, about 300 nm) of the film thickness using the resist pattern 14 as the mask as shown in FIG. 8. Thereby, in the subsequent CMP process, the flatness of the surface of silicon oxide film 3 embedded in the relatively large isolation groove 2 a to be formed easily in the boundary BL or element forming region DA can be improved. Here, a horn-shape projection is formed to the silicon oxide film 3 under the resist pattern 14 but this projection is polished in the subsequent CMP process.

[0080] Next, after the resist pattern 14 is removed as shown in FIG. 9, the silicon oxide film 3 is polished with the CMP method as shown in FIG. 10, leaving the silicon oxide film 3 within the isolation grooves 2, 2 a. In this case, the silicon oxide film 13 is functioned as a stopper layer for the polishing to protect this film from the scraping by utilizing the polishing rates of the silicon nitride film 13 and silicon oxide film 3. Scraping of the silicon nitride film 13 is controlled, for example, to about 60 nm. Thereafter, the silicon oxide film 3 embedded in the isolation groove 2 is densified (tightened with the burning process) by conducting the heat treatment under the temperature of about 1000° C. Next, as shown in FIG. 11, the silicon nitride film 13 is removed with the wet etching process using the hot phosphoric acid and thereafter the silicon oxide film 12 as the underlayer is then removed.

[0081] Next, as shown in FIG. 12, a p-type impurity, for example, boron (B) is ion-injected to form the p-type well 4 in the n-channel MISFET forming region of the semiconductor substrate 1 and an n-type impurity, for example, phosphorus (P) is ion-injected to form the n-type well 5 in the p-channel MISFET forming region. In addition, although not shown in the figure, an impurity is ion-injected to the channel region. Thereafter, the semiconductor substrate 1 is thermally oxidized to form a gate insulation film 6 to the surface of semiconductor substrate 1 in the thickness, for example, of about 2 nm.

[0082] Next, as shown in FIG. 13, a polycrystalline silicon film is deposited on the semiconductor substrate 1 with the CVD method and thereafter the polycrystalline silicon film is etched using the resist pattern as the mask to form the gate electrode 7 of the n-channel MISFET and p-channel MISFET. Subsequently, the semiconductor substrate 1 is subjected to the dry oxidation process under about 800° C.

[0083] Next, after the n-type well 5 is covered with the resist film, an n-type impurity, for example, arsenic (As) is ion-injected to the p-type well 4 with the gate electrode 7 of the n-channel MISFET used as the mask to form the source and drain expanding regions 9 a of then-channel MISFET. Similarly, after the p-type well 4 is covered with the resist film, a p-type impurity, for example, boron fluoride (BF₂) is ion-injected to the n-type well 5 with the gate electrode 7 of the p-channel MISFET used as the mask to form the source and drain expanding regions 15 a of the p-channel MISFET.

[0084] Next, as shown in FIG. 14, after an insulation film, for example, a silicon oxide film or silicon nitride film is deposited on the semiconductor substrate 1, this insulation film is anisotropically etched with the RIE (Reactive Ion Etching) and a side wall spacer 8 consisting of the insulation film is formed to the respective side walls of the gate electrodes 7 of the n-channel MISFET and p-channel MISFET.

[0085] Next, after the n-type well 5 is covered with the resist film, an n-type impurity, for example, arsenic is ion-injected to the p-type well 4 with the gate electrode 7 of the n-channel MISFET and the side wall spacer 8 used as the mask in order to form the source and drain expanding regions 9 b of the n-channel MISFET. In the same manner, after the p-type well 4 is covered with the resist film, a p-type impurity, for example, boron fluoride is ion-injected to the n-type well 5 with the gate electrode 7 of p-channel MISFET used as the mask in order to form the source and drain expanding region 15 b of the p-channel MISFET.

[0086] Subsequently, as shown in FIG. 15, an interlayer insulation film 10 structured, for example, with the silicon oxide film is formed on the semiconductor substrate 1. Thereafter, the surface of this interlayer insulation film 10 is flattened with the etch back method or CMP method. Then, the interlayer insulation film 10 is etched using the resist pattern as the mask to form a contact hole 11 reaching the source and drain expanding regions 9 b of the n-channel MISFET and the source and drain expanding regions 15 b of the p-channel MISFET. Although not shown in the figure, a contact hole reaching the gate electrodes 7 of the n-channel MISFET and p-channel MISFET is also formed simultaneously.

[0087] Next, as shown in FIG. 16, a metal film, for example, a tungsten (W) film is deposited on an upper layer of the interlayer insulation film 10 and a plug 16 is formed by embedding a metal film at the internal side of the contact hole 11 through the flattening of the surface of above metal film, for example, with the CMP method. Thereafter, the first layer wiring 17 is formed by etching the metal film deposited on the upper layer of the interlayer insulation film 10.

[0088] Thereafter, a wiring is formed as the upper layer of the first layer wiring 17 and moreover a surface protection film is formed to complete a logic integrated circuit device.

[0089] (Embodiment 2)

[0090] The embodiment 2 of the present invention explains the other manufacturing method to form the structure of FIG. 1 explained in the embodiment 1.

[0091]FIGS. 17 and 18 for explaining the embodiment 2 show the cross-sectional views of the essential portion of a semiconductor substrate after completion of the manufacturing processes explained in regard to FIGS. 6 to 7.

[0092] In this embodiment, the isolation grooves 2, 2 a are formed first in the depth of about 0.3 to 0.4 μm on the semiconductor substrate 1 and then the silicon oxide film 3 is deposited on the semiconductor substrate 1 with the CVD method or plasma CVD method.

[0093] Next, as shown in FIG. 17, a coated insulation film 18, for example, an SOG (Spin On Glass) film is formed as the upper layer of the silicon oxide film 3. This coated insulation film 18 can be flattened at its surface even when a fine level-difference exists due to the fluidity of film. Therefore, even if a recess is generated at the surface of the silicon oxide film 3, the surface of the coated insulation film 18 is flattened. Subsequently, the semiconductor substrate 1 is subjected to the heat treatment to remove the solvent in the coated insulation film 18 and to form the dense substrate. This heat treatment temperature is ranged, in the case of the annealing in the furnace, for example, to about 400 to 500° C. or ranged, in the case of the RTA (Rapid Thermal Annealing) , for example, to about 700 to 800° C.

[0094] Next, as shown in FIG. 18, the coated insulation film 18 is etched with the etch back method. In this case, etching is performed until the coated insulation film 18 is removed almost completely using the condition to make almost equal the etching rate of the silicon oxide film 3 and the etching rate of the coated insulation film 18 in view of flattening the surface of the silicon oxide film 3. Thereafter, as shown in FIG. 10, the silicon oxide film 3 is left within the isolation grooves 2, 2 a by polishing the silicon oxide film 3 on the silicon nitride film 2 with the CMP method.

[0095] Subsequently, the processes are identical to that explained with reference to FIG. 11 and other figures of the embodiment 1 of the present invention.

[0096] As explained above, according to the embodiment 2, the surface of the silicon oxide film 3 embedded in the relatively large isolation groove 2 a which may easily be formed in the boundary BL or element forming region DA can be flattened. Moreover, since the mask to which a resist pattern 14 used for flattening the surface of the silicon oxide film 3 in the embodiment 1 is no longer required, the manufacturing cost can be lowered in comparison with that of the embodiment 1.

[0097] (Embodiment 3)

[0098] The embodiment 3 explains the other manufacturing method to form a structure of FIG. 1 explained in the embodiment 1 with reference to FIGS. 19 to 22.

[0099] First, as shown in FIG. 19, a semiconductor substrate 1 consisting, for example, of a p-type single crystal silicon is subjected to the thermal oxidation to form on the surface thereof a gate insulation film 19 consisting of a thin silicon oxide film in the thickness of about 2 to 3 nm. Next, the first silicon film 20 in the thickness of about 50 nm and the silicon nitride film in the thickness of about 120 to 200 nm are deposited sequentially as the upper layers with the CVD method. Thereafter, the silicon nitride film 21, first silicon film 20 and gate insulation film 19 are sequentially dry-etched using the resist pattern as the mask. The first silicon film 20 is composed of a non-crystal silicon or polycrystalline silicon. Subsequently, after the resist pattern is removed, the isolation grooves 2, 2 a in the depth of about 0.3 to 0.4 μm are formed on the semiconductor substrate 1 by dry-etching the semiconductor substrate 1 with the silicon nitride film 21 used as the mask. In the dummy region FA, the first dummy pattern DP₁ and second dummy pattern DP₂ are provided so that the total region does not become the isolation groove.

[0100] Next, although not shown in the figure, after a thinner silicon oxide film is formed in the thickness of about 10 to 30 nm to the exposed surface of the semiconductor substrate 1, the silicon oxide film 3 is deposited in the thickness of about 600 to 700 nm on the semiconductor substrate 1 with the CVD method or plasma CVD method as shown in FIG. 20. Thereafter, as shown in FIG. 21, the silicon oxide film 3 is left in the isolation grooves 2, 2 a in the same manner as that explained with reference to FIGS. 8 to 10 of the embodiment 1 explained above.

[0101] Next, as shown in FIG. 22, the silicon nitride film 21 is removed with the wet-etching using hot phosphoric acid. In this case, the first silicon film 20 is not removed and is used as a part of the gate electrodes of the CMOSFETs C₁, C₂, C₃. Thereafter, a p-type impurity is ion-implanted in order to form the p-type well 4 in the n-channel MISFET forming region of the semiconductor substrate 1 and an n-type impurity is also ion-implanted in order to form the n-type well 5 in the p-channel MISFET forming region. Moreover, although not shown in the figure, an impurity is ion-implanted to the channel region. Thereafter, the second silicon film 22 is formed on the semiconductor substrate 1 and the gate electrodes of the CMOSFETs C₁, C₂, C₃ with the laminated layer consisting of the first silicon film 20 and second silicon film 22.

[0102] The subsequent processes are identical to that explained with reference to FIG. 13 and successive figures of the embodiment 1 and therefore the similar explanation is omitted here.

[0103] As explained above, according to the embodiment 3, kink generated in the drain current-gate voltage characteristic resulting from the roundness at the end portion of the isolation groove due to the fall of the silicon oxide film 3 embedded in the element isolation region IS can be prevented by using the first silicon film used to form the element isolating region IS as a part of the gate electrodes of the CMOSFETs C₁, C₂, C₃.

[0104] (Embodiment 4)

[0105] An placement example of the other dummy patterns as the embodiment 4 will be explained with reference to FIGS. 23 and 24. FIG. 23 is a plan view of the essential portion showing the other example of a logic integrated circuit device and FIG. 24 is a plan view for explaining a pitch and a size of the dummy pattern.

[0106] As shown in FIG. 23, like the embodiment 1, the internal side of the boundary BL indicated with a broken line is the element forming region DA where semiconductor elements are formed and the CMOSFETs C₁, C₂, C₃ are formed in this region. Moreover, the external side of the boundary BL is the dummy region FA where the semiconductor elements are not formed.

[0107] In the dummy region FA, the rectangular third dummy pattern DP₃ which is larger than the first and second dummy patterns PD₁, PD₂ is also placed in addition to these first and second dummy patterns. Namely, three kinds of dummy patterns of different shapes and areas (first dummy pattern DP₁, second dummy pattern DP₂, third dummy pattern DP₃) are regularly placed in the dummy region FA. The third dummy pattern DP₃ is formed of a rectangular semiconductor island (indicated as the thin hatching area in FIG. 23) corresponding to the active region AC.

[0108] As shown in FIG. 24, the size Laa of the longer side and the size La of the short side of the third dummy pattern DP₃ are set larger than the size Lb of a side of the second dummy pattern DP₂, but the size of space against the adjacent third dummy pattern DP₃ is identical to the size Ls of the space against the adjacent second dummy pattern DP₂.

[0109] Moreover, the size of a side of the third dummy pattern DP₃ is equal to an integer times of the pattern size obtained by adding the space size Sa to the size Lb of a side of the second dummy pattern DP₂ both in the row and column directions and satisfies the relationships of Laa+Sa=N1(Lb+Sa), La+Sa=N2×(Lb+Sa) (N1, N2 is respectively integer 1 or larger (N1, N2≧1)). Thereby, since it is possible to regularly locate a plurality of first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃ in different sizes to the dummy region FA, if the coordinate data at the time of generating a mask increases, increase of arithmetic processing time of the computer can be controlled.

[0110] Placement data of the first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃ is generated in the same manner as the method of generating the placement data of the first dummy pattern DP₁, second dummy pattern DP₂ explained with reference to the process diagram of FIG. 5 in the embodiment 1.

[0111] First, the placement prohibiting region (element forming region DA) of the first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃ is obtained. Next, the third dummy pattern DP₃ is provided extensively to the greater part of the dummy region FA. For example, after the mesh is generated in the third pitch to the entire part of the semiconductor substrate 1, the mesh overt the placement prohibiting region of the first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃ is removed. Thereafter, the third dummy pattern DP₃ is placed to the mesh. Here, the third pitch has one side in the pattern size (Laa+Sa) obtained by adding the space size Sa to the size Laa of a longer side of the third dummy pattern DP₃ and also has the other side in the pattern size (La+Sa) obtained by adding the space size Sa to the size La of the shorter side of the third dummy pattern DP₃.

[0112] Next, the placement prohibiting region of the first dummy pattern DP₁ is obtained. The placement prohibiting region of the first dummy pattern DP₁ is obtained by adding the region where the third dummy pattern DP₃ are extensively provided to the placement prohibiting region of the first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃. Next, the first dummy pattern DP₁ is provided extensively to the entire part of the dummy region FA. For example, after the mesh is generated in the first pitch in the entire part of the semiconductor substrate 1, the mesh over the placement prohibiting region of the first dummy pattern DP₁ is removed. Thereafter, the first dummy pattern DP₁ is placed in the mesh. Here, the first pitch is identical to the pattern size (La+Sa) obtained by adding the space size Sa to the size La of a side of the first dummy pattern DP₁.

[0113] Next, the placement prohibiting region of the second dummy pattern DP₂ is obtained. The placement prohibiting region of the second dummy pattern DP₂ is defined by adding the region where the first dummy pattern DP₁ and third dummy pattern DP₃ are provided extensively to the placement prohibiting region of the first dummy pattern DP₁, second dummy pattern DP₂ and third dummy pattern DP₃. Next, the second dummy patterns DP₂ are provided extensively. For example, after the mesh is generated in the second pitch in the entire part of the semiconductor substrate 1, the mesh over the placement prohibiting region of the second dummy pattern DP₂ is removed. Thereafter, the second dummy patterns DP₂ are placed in the mesh. Here, the second pitch is identical to the pattern size (Lb+Sa) obtained by adding the space size Sa to the size Lb of a side of the second dummy pattern DP₂.

[0114] As explained above, according to the embodiment 1, the dummy pattern is cable of selecting the desired shape without relation to the size of area thereof and it is also possible to combine three kinds or more kinds of dummy patterns. Therefore, a degree of freedom for placement of dummy pattern can be increased and the flatness at the surface of the silicon oxide film 3 embedded into the isolation grooves 2, 2 a can also be improved. Moreover, increase of mask data can be controlled by increasing the number of placements of the dummy patterns DP₃ of relatively large area.

[0115] (Embodiment 5)

[0116] A placement example of dummy pattern of wiring will then be explained with reference to FIGS. 25 to 27 as the embodiment 5. FIG. 25 is a plan view of the essential portion showing an example of the dummy pattern of wiring. FIG. 26 is a plan view for explaining a pitch and a size of the dummy pattern of wiring. FIG. 27 is a cross-sectional view of the essential portion showing an example of a logic integrated circuit device using a dummy pattern of wiring.

[0117] A dummy wiring system is one of the methods for overcoming disadvantages resulting from level difference at the surface in the wiring process. This system is a method for extensively providing dummy patterns (conductive islands) consisting of the material same as that of wiring to the entire part among the wirings. This method is very effective for flattening of the insulation film covering the wirings and moreover alleviation of level difference at the surface. The embodiment 5 in which the present invention is adapted to this dummy wiring system will be explained hereunder.

[0118] As shown in FIG. 25, the internal side of the boundary BL indicated with a broken line is the element forming region DA where wirings ML are formed and the external side of the boundary BL is the dummy region FA where wirings ML are formed.

[0119] In the dummy region FA, a plurality of first dummy wirings DML₁ of relatively wider area consisting of the same conductive layer as the wiring ML and a plurality of second dummy wirings DML₂ of relatively smaller area are placed regularly.

[0120] As shown in FIG. 26, the first dummy wiring DML₁ occupying relatively wider region of the dummy region FA is formed of a rectangular conductive island (indicated as relatively thinner hatched region in FIG. 25) having a size of longer side of Lca and a size Lc of shorter side and the second dummy wiring DML₂ is formed of a square conductive island (indicated as relatively thicker hatched region in FIG. 25) having a size Ld in a side of both row and column directions.

[0121] Moreover, the row-to-row space size among the adjacent first dummy wiring DML₁ and the row-to-row space size among the adjacent second dummy wiring DML₂ are set to the identical space size Sc, while the column-to-column space size among the adjacent first dummy wiring DML₁ and the row-to-row space size among the adjacent wiring DML₂ are set to the identical space size Sd. The widths Lca, Lc of the first dummy wiring DML₁ and the width Ld of the second dummy wiring DML₂ are set to the minimum line width or larger required for the lithography technique and dry-etching technique and the spaces Sc, Sd are set to the minimum space width or larger required for the lithography technique and dry-etching technique.

[0122] Here, the pattern size identical to the size Lca of longer side of the first dummy wiring DML₁+space size Sc is an integer times of the pattern size identical to the size Ld of a side of the second dummy wiring DML₂+space size Sc and satisfies the relationship of Lca+Sc=N(Ld+Sc) (N is integer 1 or larger (N≧1)). In the same manner, the pattern size identical to the size Lc of shorter side of the first dummy wiring DML₁+space size Sd is an integer times of the pattern size identical to the size Lc of shorter side of the first dummy wiring DML₁+space size Sd and satisfied the relationship of Lc+Sd=N(Ld+Sd) (N is integer 1 or larger (N≧1)).

[0123]FIG. 27 is a cross-sectional view of the essential portion of the semiconductor substrate showing an example of a logic integrated circuit device to which the dummy wiring system of the embodiment 5 is adapted.

[0124] For example, an interlayer insulation film 10 is formed covering the CMOSFETs C₁, C₂, C₃ shown in FIG. 2 of the embodiment 1 and the first layer wiring 17 is formed on the interlayer insulation film 10. The surface of the interlayer insulation film 10 is flattened with the CMP method or etch-back method. Moreover, the first layer wiring 17 is covered with the interlayer insulation film 23. The surface of the interlayer insulation film 23 is flattened with the etch-back method or the like.

[0125] At the upper layer of the interlayer insulation film 23, the second layer wiring 24 and a dummy wiring 25 are formed. Here, as the dummy wiring 25, for example, the first dummy wiring DML₁ and second dummy wiring DML₂ are used. The second layer wiring 24 and dummy wiring 25 are composed of the same material and is formed in the same process. As a material thereof, for example, a metal material such as aluminum (Al) or copper (Cu) may be used.

[0126] The second layer wiring 24 and dummy wiring 25 are covered with the interlayer insulation film 26. The interlayer insulation film 26 is, for example, silicon oxide film, SOG (Spin On Glass) and lamination layer film consisting of silicon oxide film and the silicon oxide film explained above may be a TEOS oxide film that is deposited with the plasma CVD method using TEOS (Tetra Ethyl Ortho Silicate: Si(OC₂H₅)₄) and ozone (O₃) as the source gas. The surface of the interlayer insulation film 26 is polished with the CMP method and this surface is also flattened by utilizing the dummy wiring 25 (first dummy wiring DML₁, second dummy wiring DML₂).

[0127] Moreover, the third layer wiring 27 is also formed as the upper layer of the interlayer insulation film 26 to form, although not shown in the figure, a passivation film as the upper-most insulation film.

[0128] Here, in this embodiment 5, the dummy wiring 25 is laid in the process to form the second layer wiring 24, but the dummy wiring may also be placed in the process to form the first layer wiring 17 or the third layer wiring 27. Moreover, even when the upper layer wiring is laid on the third layer wiring 27, the dummy wiring can also be placed in the process to form these wirings.

[0129] As explained above, according to the embodiment 5, since the dummy wiring 25 can be placed to the entire region of the dummy region FA by utilizing the first dummy wiring DML₁ of relatively large area and the second dummy wiring DML₂ of relatively small area, the flatness of the surface of the interlayer insulation film 26 formed as the upper layer of the second layer wiring 24 can be improved. Moreover, since the first dummy wiring DML₁ of relatively large area occupies the relatively wider region of the dummy region FA, the number of placements of the second dummy wiring DML₂ of relatively small area can be relatively reduced and thereby increase of mask data amount can be controlled.

[0130] The preferred embodiments of the present invention have been explained above but the present invention is never restricted to these embodiments and naturally allows various changes and modifications within the scope of the claims thereof.

[0131] For example, in above embodiments, square and rectangular shapes are selected as the shape of dummy pattern, but the shape of dummy pattern is never restricted thereto and triangular shape, trapezoidal shape, circular shape or the other polygonal shape may also be selected for the dummy pattern.

[0132] The effects of the typical inventions of the present invention will be briefly explained as follows.

[0133] According to the present invention, the flatness of member surface embedded to a plurality of recesses can be improved by placing at least two dummy pattern groups.

[0134] Moreover, since the dummy pattern of relatively large area occupies the relative wider area of the dummy region, increase in time required for generation of mask can be controlled by suppressing increase of coordinate data amount required for generation of mask. Accordingly, the flatness of member surface embedded in a plurality of recess can be improved without increasing the time required for manufacturing process of the semiconductor device. 

What is claimed is:
 1. A semiconductor device comprising an element forming region wherein circuit elements are specified with the boundary on the main surface of a semiconductor substrate and a dummy region, where circuit elements are not formed, adjacent to said boundary, wherein said dummy region includes at least two dummy pattern groups, a plurality of patterns of the same shape and the same size occupying the surface are placed in isolation in both row and column directions in each dummy pattern group, and sizes in the row and/or column direction of a plurality patterns are respectively different among the dummy pattern groups.
 2. A semiconductor device according to claim 1, wherein when the sizes in the row and/or column direction of a plurality of patterns forming the first dummy pattern group among said dummy pattern groups are smallest, the size identical to the size of a side of one pattern among said first dummy pattern group+space size is specified to the 1/integer of the size identical to the size of a side of one pattern in the other pattern group+space size among adjacent patterns in both row and column directions.
 3. A semiconductor device according to claim 1 or 2, wherein the space size in the row direction among the adjacent patterns is identical among said dummy pattern groups and the space size in the column direction among the adjacent patterns is identical among said dummy pattern groups.
 4. A semiconductor device according to claim 1 or 2, wherein shape of a plurality of said patterns is square or rectangular shape.
 5. A semiconductor device according to claim 1 or 2, wherein a plurality of said patterns are semiconductor islands isolated with each other with the isolation groove formed on the main surface of said semiconductor substrate.
 6. A semiconductor device according to claim 1 or 2, wherein a plurality of said patterns are conductive islands formed of the conductive layer same as that used for wiring provided on the main surface of said semiconductor substrate.
 7. A semiconductor device comprising an element forming region where circuit elements are specified with the boundary on the main surface of a semiconductor substrate and a dummy region, where circuit elements are not formed, adjacent to said boundary, wherein said dummy region has at least two dummy pattern groups, a plurality of semiconductor islands of the same shape and same size occupying the main surface are placed, in each dummy pattern group, in isolation in the row and column directions with the isolation groove in which the insulation film is embedded and sizes of the row direction and/or column direction of a plurality of said semiconductor islands are different among the dummy pattern groups.
 8. A semiconductor device comprising an element forming region where wiring is specified with the boundary on the main surface of a semiconductor substrate and a dummy region where wiring adjacent to said boundary is not formed, wherein said dummy region has at least two dummy pattern groups, a plurality of conductive islands formed with the conductive layer same as said wiring of the same shape and same size occupying the surface are placed, in each dummy pattern group, in isolation in both row and column directions with the insulation film, and the sizes of a plurality of said conductive islands in the row and/or column direction are different among the dummy pattern groups.
 9. A method of manufacturing a semiconductor device where an element forming region in which circuit elements are formed and a dummy region in which circuit elements are not formed are specified with the boundary and at least two dummy pattern groups are formed in said dummy region, comprising the steps of: (a) forming, on the main surface of the semiconductor substrate, the first isolation groove for specifying the active region of said element forming region and the second isolation groove for dividing a plurality of semiconductor islands forming a dummy pattern group in both row and column directions; (b) an insulation film covering said element forming region and said dummy region in such a manner as embedding said first isolation groove and said second isolation groove; and (c) removing the external insulation film of said first isolation groove and second isolation groove by polishing said insulation film, whereby a plurality of semiconductor islands of the same shape and the same size occupying the surface are formed in each dummy pattern group but sizes of a plurality of said semiconductor islands in the row direction and/or column direction are different among the dummy pattern groups.
 10. A method of manufacturing a semiconductor element according to claim 9, further comprising the process to form a resist pattern covering the relatively wide isolation groove prior to said process (c) and to etch the upper part of said insulation film not covered with said resist pattern.
 11. A method of manufacturing a semiconductor device where an element forming region in which circuit elements are formed and a dummy region in which circuit elements are not formed are specified with the boundary and at least two dummy pattern groups are formed in said dummy region, comprising the steps of: (a) forming the first isolation groove for specifying an active region of said element forming region on the main surface of a semiconductor substrate and the second isolation groove for dividing a plurality of semiconductor islands forming said each dummy pattern group of said dummy region in both row and column directions; (b) depositing an insulation film covering said element forming region and said dummy region in such a manner as embedding said first isolation groove and second isolation groove and thereafter depositing the coated insulation film at the upper layer of said insulation film; (c) removing said coated insulation film with the etch-back method and moreover flattening the surface of said insulation film; and (d) removing said insulation film in the external side of said first isolation groove and said second isolation groove by polishing said insulation film; whereby a plurality of semiconductor islands of the same shape and the same size occupying the surface are formed in each dummy pattern group but sizes of a plurality of said semiconductor islands in the row direction and/or column direction are different among the dummy pattern groups.
 12. A method of manufacturing a semiconductor device where an element forming region in which circuit elements are formed and a dummy region in which circuit elements are not formed are specified with the boundary and at least two dummy pattern groups are formed in said dummy region, comprising the processes of: (a) depositing the first insulation film, the first silicon film and the second insulation film forming a gate insulation film on the semiconductor substrate; (b) forming the first isolation groove for specifying an active region of said element forming region and the second isolation groove for dividing a plurality of semiconductor islands forming said each dummy pattern group of said dummy region by etching said second insulation film, said first silicon film, said first insulation film and said semiconductor substrate; (c) depositing the third insulation film covering said element forming region and said dummy region in such a manner as embedding said first isolation groove and said second isolation groove; (d) removing said third insulation film at the external side of said first isolation groove and said second isolation groove by polishing said third insulation film; (e) depositing the second silicon film on said semiconductor substrate after removing said second insulation film; and (f) forming a gate electrode by processing said second silicon film and said first silicon film; whereby a plurality of semiconductor islands of the same shape and the same size occupying the surface are formed in each dummy pattern group but sizes of a plurality of said semiconductor islands in the row direction and/or column direction are different among the dummy pattern groups.
 13. A method of manufacturing a semiconductor device according to any one of claims 9 to 12, wherein when the sizes in the row and/or column direction of a plurality of semiconductor islands forming the first dummy pattern group among said dummy pattern groups are smallest, the size identical to the size of a side of one semiconductor island among said first dummy pattern group+space size is specified to the 1/integer of the size identical to the size of a side of one semiconductor island in the other pattern group+space size among adjacent semiconductor islands in both row and column directions.
 14. A method of manufacturing a semiconductor device according to claim 9, 10 or 11, wherein a silicon oxide film, a silicon nitride film are sequentially formed from the lower layer under said insulation film and said silicon nitride film functions as a stopper layer in the process to polish said insulation film.
 15. A method of manufacturing a semiconductor device according to claim 12, wherein said second insulation film is formed of a silicon nitride film, while said second insulation film functions as a stopper layer in the in the process to polish said third insulation film.
 16. A method of manufacturing a semiconductor element where an element forming region in which wiring is formed and a dummy region in which wiring is not formed are specified with the boundary and at least two dummy pattern groups are formed in said dummy region, comprising the processes of: (a) forming wiring in said element forming region by patterning the conductive film deposited on a semiconductor substrate and then forming a plurality of conductive islands placed in the row and column directions to form each dummy pattern group in said dummy region; (b) depositing an insulation film covering said wiring and a plurality of said conductive islands; and (c) flattening the surface of said insulation film, whereby a plurality of semiconductor islands of the same shape and the same size occupying the surface are formed in each dummy pattern group but sizes of a plurality of said semiconductor islands in the row direction and/or column direction are different among the dummy pattern groups.
 17. A method of manufacturing a semiconductor device according to claim 16, wherein when the size in the row and/or column direction of a plurality of conductive islands forming the first dummy pattern group among said dummy pattern groups is smallest, the size identical to the size of a side of one conductive island in said first dummy pattern group+the space size among adjacent conductive islands is specified to 1/integer of the size identical to the size in both row and column directions of a side of one conductive island in the other dummy pattern group+the space size among the adjacent conductive islands.
 18. A method of designing a semiconductor device, where an element forming region on the main surface of a semiconductor substrate in which circuit elements are specified with the boundary and a dummy region in which circuit elements adjacent to said boundary are not formed are comprised, said dummy region includes at least two dummy pattern groups, a plurality of patterns of the same shape and same size occupying the surface are placed in isolation in the row and column directions in each dummy pattern group, and the sizes in the row and column directions of a plurality of said patterns are different among the dummy pattern groups, comprising the process of: placing a plurality of patterns for said each dummy pattern group after said element forming region and said dummy region are specified with the boundary; whereby a mesh in the size identical to the size of a side of a pattern forming a dummy pattern group+the space size among the adjacent patterns is generated for each dummy pattern group and a pattern is placed within said mesh in the region other than the pattern placement prohibiting region.
 19. A method of designing a semiconductor device according to claim 18, wherein when the size in the row and/or column direction of a plurality of patterns forming the first dummy pattern group among said dummy pattern groups is smallest, the size identical to the size of a side of one pattern in said first dummy pattern group+the space size among adjacent patterns is specified to 1/integer of the size identical to the size in both row and column directions of a side of one pattern in the other dummy pattern group+the space size among the adjacent patterns.
 20. A method of designing a semiconductor device according to claim 18 or 19, wherein the space size in the row direction among the adjacent patterns is identical among said dummy pattern groups and the space size in the column direction among the adjacent patterns is identical among said dummy pattern groups.
 21. A method of designing a semiconductor device according to claim 18 or 19, wherein the shape of a plurality of said patterns is the square or rectangular shape. 